In an electrical characteristics test for a semiconductor integrated circuit such as an IC chip, a probe unit is used that houses a plurality of conductive probes at predetermined positions corresponding to an arrangement pattern of external electrodes included in the semiconductor integrated circuit. The probe unit includes a probe holder that has a plurality of hole portions into which contact probes are inserted, and, both end portions of the conductive probe held by the probe holder are brought into contact with an electrode of the semiconductor integrated circuit and an electrode of a circuit substrate for outputting a test signal, respectively, to electrically connect the semiconductor integrated circuit and the circuit substrate (see Patent Document 1 for example).    Patent Document 1: Japanese Laid-open Patent Publication No. 2002-107377